Permutation switch



y 1961 R. w. DAVIDSON 2,984,717

PERMUTATION SWITCH Filed June 22, 1959 2 Sheets-Sheet 1 INVENTOR. HA YMOND WflA wosozv ATTOR/VE KS y 1961 R. w. DAVIDSON 2,984,717

PERMUTATION SWITCH Filed June 22, 1959 2 Sheets-Sheet 2 INVENTOR. HA rmo/vo WDAv/0s0/v Arm/away:

United States Patent 9 PERMUTATION SWITCH Raymond W. Davidson, Van Nuys, Califi, assignor to Max-A-Loc Inc., Van Nuys, Califi, a corporation of California This invention relates to permutation switches of the general type disclosed in U.S. Letters Patent No. 2,797,271, issued in the name of Arthur L. Augustine on June 25, 1957. The general object of the present invention is to improve upon the type of switch shown in that patent, which is one wherein a plurality of disc-like tumblers arranged for free rotation upon a tubular dead shaft mounted in one end of a case, are provided with segmental peripheries consisting in respective conductor and insulator segments, and are arranged for engagement of said peripheries by a plurality of contact brushes which are mounted on the inside of the lateral wall member of the case and project radially inwardly into contact with the tumbler peripheries. In one form of the invention, the majority of each tumbler periphery is constituted by an insulator surface and a small segment thereof is of conducting material, and each pair of adjoining tumblers is bridged by a bifurcated brush having legs adapted to contact the conductor segments of the adjoining tumblers whereby, when the tumblers are aligned, a circuit will be completed through an aligned series of contact segments of the full series of tumblers. In another form of the invention, the majority of each tumbler periphery is of conducting material (e.g. the entire body of the tumbler may be of metal) and a relatively short segment of each tumbler periphery is of insulating material. The arrangement in this form of the invention is such that the insulator segments must all be lined up in contact with the respective brushes in order to break a circuit normally existing when the tumblers are not aligned. A particular object of the invention is to provide an improved construction of brush mounting means removably mounted within the case of the switch. A further object is to provide an improved construction and arrangement of brushes having contact shoes engageable with notched tumbler peripheries so as to function both as circuit establishing contact means and as detent means for assisting the operator in correctly positioning the tumblers at their designated positions for switch actuation in a series of rotations of the switch actuator (e.g. knob) in opposite directions of rotation in accordance with conventional operation of a permutation lock or similar device.

A further object is to provide an improved tumbler construction including a tumbler body and an insert segment of formed sheet material which is recessed or inlaid into the tumbler so as to constitute a flush continuation of the tumbler surface.

A further object is to provide a permutation switch having an improved construction which is relatively inexpensive, completely dependable in operation, easily assembled, and readily disassembled for servicing.

Other objects and advantages will become apparent in the ensuing specification and appended drawing in which:

Fig. 1 is an axial sectional view of a permutation switch embodying my invention;

Fig. 2 is a transverse sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is a fragmentary exploded sectional view illustrating the means for anchoring the contact brushes to the case of the switch;

Fig. 4 is an internal plan view of the assembly of brushes and mounting plate with some of the parts broken away and removed;

Fig. 5 is a plan view of the brush securing leaf;

Fig. 6 is an end view of one of the tumblers;

Fig. 7 is a perspective view of a tumbler contact segment;

Fig. 8 is a fragmentary sectional view, on an enlarged scale, of a conductor segment mounting in a tumbler;

Fig. 9 is a schematic view of a normally closed switch embodying a modified form of the invention;

Fig. 10 is an end view of a tumbler thereof;

Fig. 11 is an end view of an actuator arm and tumbler disc assembly embodying an improved modified connection between the actuator arm and the live shaft of the apparatus.

Referring now to the drawings in detail, I have shown therein, as an example of one form in which the invention may be embodied, a permutation switch including a case indicated generally at 9, having a cylindrical lateral wall member 10, a mounting flange 11 at the forward end thereof, and an end wall 12 closing the forward end of the case. Case 10 has its rear end closed by a removable cap 13. Flange 11 is adapted to mount the switch against a panel 14 which may have an opening through which the case extends as indicated. The case 9 may be secured to panel 14 by means of bolts 15 extended through the cap 13 and suitably anchored as by threading into longitudinal bores in integral bosses 16 formed internally in the wall member 10. End member 12 is formed with an integral central boss 17 in which is securely mounted a reduced end portion of a tumbler supporting dead shaft 18 of cylindrical sleeve form. The opposite end of dead shaft 18 is spaced from the end cap 13. Journalled within a cylindrical axial bore in dead shaft 18 is an actuator shaft 19 to the forward end of which is secured a dialing knob 20. Knob 20 has a collar flange 21 hearing indicator marks which cooperate with an indicator mark on the rim 22 of mounting flange 11.

Rotatably mounted upon dead shaft 18 are a plurality of tumblers 23, 24, 25, 26, each having a cylindrical annular hub 27 provided with a cylindrical bore which receives the dead shaft 18. Each of the tumblers 23-26 includes a flat radial web 28 and a cylindrical rim 29, web 28 being at one side of the disc, and hub 27 and rim 29 projecting therefrom axially in co-axial, radially spaced relation. The hub 29 projects slightly beyond the axial extremity of rim 29 so as to engage the adjoining tumbler, leaving a slight axial clearance space between the rims of the adjacent tumblers. Each of the tumblers 23-26 is generally in the form of a flat circular disc with an annular recess 30 therein, open at one side thereof.

Preferred form of invention-Figs. 1-8

Where the switch is of a normally open type as disclosed in the drawings, the tumblers 23-26 are of insulating material and are preferably of synthetic resin plastic, injection molded. A relatively rigid, form retaining material is utilized. Other suitable materials are hard rubber, a high strength ceramic material, or a metal stamping adequately coated with a coating of insulating material.

Each of the tumblers 23-26 has a pair of integral, axially extending driving teeth 31 and 32, the latter projecting axially from the inner side of web 28 into the annular recess 30 of its respective tumbler and the former projecting axially outwardly from the outer side of web 28. Driving teeth 31 and 32, being in alignment with one another in their respective tumbler, are arranged substantially at a common radius from the axis of shaft teeth 31 are in the form ofstuds sufliciently narrowed to project into the respective recesses 30, clearing both the rims 29 and hubs 27 thereof. As indicated in Fig. 2, they may be in the form of cylindrical studs. The driving teeth 32, on the other hand, are preferably in the form of radial webs joined not only to the respective webs '28 but also bridging between and joined to the respective hubs 27 and rims 29, as shown in Fig. 6. Thus the driving teeth 32 function as reinforcing webs as well as driving elements.

The driving tooth 31 of the rearmost tumbler 26 projects rearwardly beyond the tumbler assembly for interengagement with a drive transmitting arm 34 which is secured to shaft 18, and projects radially therefrom so that its sweep path is intercepted by the driving tooth 31.

Each of the tumblers 2326 has in its rim 29 a series of V-notches 35 which are directly adjoining so as to define between them respective transverse ridges of triangular section. Each tumbler also has a short peripheral segment 36 which has notches corresponding to and constituting continuation of the notches 35 of the respective tumbler body. Segments 36 are of stamped sheet metal, of yoke form, and each segment comprises a notched peripheral web portion 35 and a pair of radially extending fiat parallel ears 37 which embrace the respective sides of a respective tumbler body, arereceived in shallow radial recesses 38, in the respective sides of the respective rim 29, and are provided with respective apertures 39 in which are locked a pair of small integral studs 40 integral with hte respective tumbler rim 29 and projecting axially from the bottoms of the respective radial recesses 38 thereof. The segment 36 is assembled on its respective tumbler by spreading the ears 37, springing them over the studs 40, and allowing them to spring back around the studs 40.

A series of contact brushes 41, 42, 43, 44 and 45 are arranged to bearagainst the peripheries of the respective tumblers 23, 24, 25 and 26, the brushes 42, 43 and 44 being of bifurcated form and in bridging relation to adjoining tumblers and the brushes 41 and 45 being of single-leg form and engaging only the forward and rear terminal tumblers. Each of the brushes, whether of single-leg or bifurcated form, is of Z-configuration as viewedfromthe side in Fig. 2, the brushes 42, 43 and :44 each includinga pair of radially extending legs 46 and'the brushes 41, 45 each having a single leg 46'. Each brush further includes an integral contact shoe 47 .bent circumferentially from the inner end of leg 46, and

a mounting tab 48 bent circumferentially in the opposite direction from the outer end of the leg 46. Tab 48 terminates in an abutment flange 49 bent radially inwardly. It is provided with two circumferentially spaced apertures '50 (Fig. 3) adapted to receive correspondingly spaced integral studs 51 projecting inwardly from a mounting plate 52 of semi-cylindrical arch form.

The contact shoes 47 are of rounded bar form (eg semi-cylindrical) extending transversely parallel to notches 35, and-with a radius sufliciently small so that the shoes will enter the notches 35 with sufficient engagement therein with a yielding detent action, to yieldingly position each succeeding tumbler as it is arranged in accordance with the dialing movement of the actuator knob. Theengagement of the shoes in the notches is likewise such asto provide the operator with a response to his dialing movement such that he can feel the locating engagement of a tumbler by a respective brush or brushes as he brings 'it to a stop at the end of a stage of tumbler rotating -movement. The locating of a contact shoe in a notch also provides better electrical contact in that the shoe will engage against the pair of successive ridges defining the notch in which it locates, thus providing two lines of electrical contact instead of one.

Tab 48 is anchored to the mounting plate 52 by applying to its inner face a fastener plate 53 (Fig. 5) having a series of pairs of apertures 54 which receive the inner ends of studs 51. After assembling the parts thus, with-the tabs 48 interposed between the fastener plate 53 and a chordal inner face 59 of mounting plate 52, a hot iron is applied to the ends of studs 51 projecting through fastener plate 53 to weld the ends of the studs into the apertures 54, thus integrally joining the studs 51 to fastener plate 53, as indicated in Fig. 2. The abutment flange 49 is positioned to snugly engage one side margin of the fastener plate 53, so as to securely brace the respective brush against any tendency to rotate with a shearing action against studs 51.

Mounting are 52 is of a material having suitable insulating qualities. Preferably, it is of substantially rigid synthetic resin plastic material (it can be the same ma terial as the bodies of tumblers 23-26) and is preferably injection molded to fit snugly within the arcuate space defined between circumferentially spaced abutment shoulders 55 (sides of bosses 16) and the semi-cylindrical internal wall of lateral wall member 10 of the case between the shoulders 5. In assembling the switch, the mounting plate 52 is inserted endwise (parallel to the axis of shaft 19) into the case through the open rear end thereof and is secured in place by attachment of the cap 13 to the case, closing the rear end.

In the normally open switch disclosed herein, each of the bridging brushes 4-2, 43 and 44 is bifurcated, having a pair of axially spaced legs 46 joined by its mounting tab 48, the pair of legs of each bifurcated brush being in straddling relation toadjacent tumblers, with one leg engaging the periphery of one tumbler and the other leg engaging the periphery of the adjacent tumbler. The terminal brushes 41 and 45 are arranged with their single legs 46 engaging the terminal tumblers 23 and 26 adjacent the outer sides thereof, and are connected to respective conductors 56 and 57 which are brought through a suitable aperture or apertures in the wall of the case, such as the aperture 58 in cap 13. It may now be noted that the cylindrical periphery of each tumbler is engaged by two axially spaced brush legs 46 (or 46 and 46') the legs being aligned with one another in a line parallel to the axis of shaft 19. Consequently, in the normally open switch shown, when all of the conductor segments 36 are aligned parallel to the axis, a circuit will be completed between the conductors 56 and 57 through the terminal brushes 41, 45 and the bridging brushes 42, 43 and 44.

Modified form-Figs. 9 and 10 The invention contemplates an alternative arrangement wherein the switch is normally closed. Such an arrangement is shown in Figs. 9 and 10, and involves primarily the substitution of a series of tumblers 23a, 24a, 25a, and 26a consisting in body members of metal or other conductive material (e.g. die castings) and each having a short segment 36a of insulating material (with the exception of tumbler 23a) which has a segment 36b corresponding to a segment 36a with the exception that it extends only half the axial width of the tumbler instead of entirely traversing the periphery as in the case of segment 36a.

Brushes 42, 43 and 44 are arranged in bridging relation to the tumblers the same as in Fig. l, and brushes 41 and 45 are single leg brushes arranged to engage the outer sides of the respective terminal tumblers 23a and 26a. The outer half of the peripheral area of tumbler 23a has a full 360 conducting surface and thus brush 41 is constantly'in electrical contact with tumbler 23a. The

tumblers 23a, 24a, 25a and 26a are in conducting contact with one another through their metallic hubs 27a, but may be insulated from the case by utilizing insulating material (e.g. a suitable hard plastic) for the dead shaft 18a on which the tumblers are rotatably mounted, and by utilizing insulating material in the rotation transmiting arm 34a. The driving elements 31a and 32a may be identical with the driving elements 31 and 32 of Fig. l with the exception of being formed of metal, integrally with their respective tumblers.

Instead of the series arrangement of the brushes in the electrical circuit of the switch, shown in Fig. 1, the normally closed switch of Figs. 9 and utilizes a seriesparallel arrangement wherein the brushes 42, 43, 44 and 45 are all connected to the conductor 57a in parallel as indicated, whereas the terminal brush 41a is connected separately to the conductor 56a and is not connected to the other brushes or to conductor 57a except through the tumblers.

It will now be apparent that in the operation of the switch shown in Fig. 9, a conducting connection will be maintained through the switch at all times, from conductor 56a through brush 41 to tumbler 23a (which connection is never broken) thence from tumbler 23a to the succeeding tumblers 24a, 25a and 2611 through their constantly maintained hub connections, and thence from any one of the tumblers to the conductor 57a through any brush 42, 43, 44 or 45 which has a leg thereof in contact with a metal peripheral segment of any one of the tumblers. Thus it becomes necessary to operate the switch to align all of the insulator segments 36a and 36b so that all legs of all brushes except the brush 41 are resting upon insulator segments, in order to break the circuit between the brush 41 and the remaining brushes.

While the insulation of the four tumblers from the case may be desirable for some installations, there may be others wherein it will not be objectionable to have the case grounded to the ground side of the circuit, which may be the conductor 55a, and in such a case it would be possible to utilize metal connections between the case and the tumblers in the dead shaft 18a and operating arm 34a, and it would only be necessary to maintain insulation between the brushes 42, 43, 44, 45 and the conductor 56a on the one hand and the case on the other hand, in order to have a satisfactorily operating arrangement.

In a modified form of the invention shown in Fig. 11, in lieu of the splined connection between actuator arm 34 and shaft 19 of Fig. 2, there is provided an improved, more readily disassembled connection between the actuator arm 34b and a squared end 1% on the live shaft 19, the squared end 19b extending through a fitted squared aperture in arm 34b and being secured by a cotter key, as shown, extended through a diametral aperture in the squared end 1%.

I claim:

1. In a permutation switch: a case of cup shape having an end wall member at one end thereof, having a lateral Wall member; a dead shaft of cylindrical sleeve form having one end fixed to said end wall member and having a free end spaced from the other end of the case; a plurality of circular disc-like tumblers having cylindrical hub bores receiving said dead shaft and rotatable thereon, each of said tumblers having a periphery comprising respectively a conductor contact segment and an insulator segment; a plurality of conductor brushes each having an inner end bearing upon the periphery of a respective tumbler for alternative engagement with a contact segment or an insulator segment depending upon the position of rotation of the tumbler and each extending generally radially outwardly and having at its outer end a mounting tab extending circumferentially and terminating in a transverse, inwardly projecting abutment flange; an arched mounting plate of insulating material having a concave inner face and having integral studs projecting through apertures in the tabs of the respective brushes; and a fastener plate of insulating material in clamping engagement with the respecive tabs and integrally united to the ends of said studs to maintain said clamping engagement, said plate having one side thereof abutted against the respective abutment flanges of said tab, to brace the brushes against rotative movement with respect to said studs; said case having integral internal shoulders circumferentially spaced in accordance with the arcuate extent of said mountnig plate, said mounting plate being secured in said case by abutting engagement of its ends with the respective shoulders, and with its outer face seated against said lateral wall member of the case, drive teeth carried by the respective tumblers and interengageable for lost motion transmission of rotation between the respective tumblers for aligning one series of said tumbler segments with said brushes to actuate the switch, said drive teeth projecting axially from the respective tumblers, inwardly of the peripheries thereof, one of said drive teeth projecting externally from a terminal one of said tumblers disposed adjacent the said free end of said dead shaft; a live shaft extending through and rotatable in said dead shaft and having one end portion projecting from and adjacent the free end of said dead. shaft; a drive transmitting member secured to said one end of the live shaft and projecting radially to a position for engagement with said externally projecting drive tooth of said terminal tumblers; and an actuator member secured to the other end of said live shaft, for transmitting rotation through the live shaft to said tumblers.

2. A permutation switch as defined in claim 1, including an end cap detachably secured to the other end of said case and closing the same, and wherein said mounting plate has one end thereof abutted against said end cap for retention against axial displacement.

3. In a permutation switch: a case of cup shape having an end wall member at one end thereof and having a lateral Wall member; a dead shaft of cylindrical sleeve form having one end fixed to said end wall member and having a free end adjacent the other end of the case; a plurality of disc-like tumblers of insulating material having respective cylindrical hub bores receiving said dead shaft and rotatable thereon, each of said tumblers having a cylindrical periphery provided with a shallow arcuate notch; a conductor contact segment of thin sheet metal in the form of a rectangular U-shaped yoke of dihedralangular configuration including a web seated in said notch and side ears extending radially inwardly from said web in snug embracing engagement with said tumbler and secured to the respective sides thereof; connector brushes mounted in the case and each bearing upon a respective tumbler periphery for engagement alternatively with a contact segment or a conductor segment depending upon the position of rotation of the respective tumbler; drive teeth carried by therespective tumblers and interengageable for lost motion transmission of rotation between the respective tumblers for aligning them in circuit establishing positions, said drive teeth including a stud projecting externally from a terminal one of said tumblers disposed adjacent the said free end of said dead shaft; a live shaft extending through and rotatable in said dead shaft and having one end adjacent and projecting from said free end of the dead shaft; a drive transmitting arm secured to the said projecting end of said drive shaft and extending radially outwardly to a point where its sweep path will be intercepted by said stud for engagement therewith; an actuator member secured to the other end of said live shaft, for transmitting rotation through the live shaft to said tumbler; said drive transmitting teeth projecting axially from the respective tumblers, inwardly of the peripheries thereof; said tumblers having peripheries collectively constituting a common cylindrical outer face of the tumbler assembly, with only slight axial spaces be tween the respective individual tumbler peripheries.

4. i In a permutation switch, a case ofcup shape includingv an end wall member at one end thereof and a substantially cylindrical lateral wall member; a cap secured toithe. end of the caseland closing it; a dead shaft of cylindrical sleeve form having one end fixed to said end wall member and having a free end spaced from said cap; a plurality of wheel-like tumblers each having respective hub and rim members defining between them, in one side thereof, an annular recess, and having on the other side thereof a radial web joining said hub and rim members and defining the bottom of said recess, each tumbler including a pair of integral drive teeth secured to and projecting axially in opposite directions from the web thereof, one of said teeth being in the form of a radial web of' spoke form, integral with said web and hub andrrimmembers andbridging between the hub and rim members within the annular recess of the respective tumbler and the other of said elements being in the form of astud projecting axially from the outer side of said Web intothe recess of an adjoining tumbler and engageable with the radial web therein, for lost motion trans- -mission of rotation between adjoining tumblers, said stud having a diameter less than the radial width of said recess, one of said studs projecting externally from a terminal one of said tumblers disposed adjacent the free end of said dead shaft, each'tumbler having a periphery comprising respectively a conductor contact segment and an insulator segment; conenctor brushes each having an outer end mounted on saidlateral wall member and having an inner end in the form of a contact shoe riding upon the periphery of a respective tumbler for alternative contact with a conductor segment or an insulator seg mentdepending upon the position of rotation of the tumbler; a live shaft extending through and rotatable in said dead shaft and having one end adjacent and projecting from said free end of the'dead shaft; a drive transmitting member secured to and projecting radially from said projecting end portion of the live shaft and positioned so that itssweep path will be intercepted by said one stud; and an actuator member secured to the other end of said live'shaft, for transmitting rotation through the live shaft and'said' drive transmitting member to the tumblers for lining up one series of said tumbler periphery segments for simultaneous contact with said brushes, whereby to actuate the switch.

5. In a permutation switch: a case of cup shape having an end wall member at one end thereof, having a lateral wall member and including a cap detachably secured to and closing its other end; a dead shaft of cylindrical sleeve form having one end fixed to said end wall member and having a free end spaced from the other end of the case; a plurality of disc-like tumblers having cylindrical hub bores receiving said dead shaft and rotatable thereon, each of said tumblers having a periphery comprising respectively 'a conductor contact segment and an insulator segment; a plurality of connector brushes each having an inner end bearing upon the periphery of a respective tumbler for alternative engagement with a contact segment or an insulator segment depending upon the position ofrotation of the tumbler and each extending generally radially outwardly and having at its outer end a mounting tab extending circumferentially and terminating in a transverse inwardlyprojecting flange; an arched mounting plate of insulating material having a concave inner'face and having integral studs projecting through apertures in the tabs of the respective brushes; and a fastener plate of insulating material in clamping engagement with the respective tabs and integrally united to the ends of said studs to maintain said clamping engagement, said plate having one side thereof abuted against the respective abutment flanges of said tabs, to brace the brushes against rotative movement with respect to said studs; said caseihaving integral internal shoulders circumferentially spaced in accordance with the arcuate extent of said mounting'plate, said mounting plate being secured in said case by abutting engagement posite directions from the respective tumblers, one of,

said drive teeth projecting externally from a terminal one of said tumblers disposed adjacent the said free end of said dead shaft; a live shaft extending through and rotatable in said dead shaft and having one end portion projecting from and adjacent the free end of said dead shaft; a drive transmitting member secured to said one end of the live shaft and projecting radially to a position for engagement with said externally projecting drive element of said terminal tumbler; and an actuator member secured to the other end of said live shaft, for transmitting rotation through the live shaft to said tumblers.

6. In a permutation switch: a case of cup shape having an end wall member at one end thereof and having a lateral wall member; a dead shaft of cylindrical sleeve form having one end fixed to said end wall member and having a free end adjacent and spaced from the other end of the case; a plurality of disc-like tumblers having respective cylindrical hub bores receiving said dead shaft and rotatable thereon, each of said tumblers having a generally cylindrical periphery, comprising relatively long and short segments circumferentially, consisting in conductor and insulator segments; conductor brushes mounted in the case and each having at its end a contact shoe. bearing upon a respective tumbler periphery for engagement alternatively with an insulator segment or a conductor segment depending upon the position of rotation of the respective tumbler; drive teeth carried by the respective tumblers, projecting axially in opposite directions therefrom, inwardly of the peripheries thereof, and interengageable for lost motion transmission of rotation between the respective tumblers for arranging them in switch-actuating alignment, one of said drive teeth projecting externally from a terminal one of said tumblers disposed adjacent the said free end of said deadv shaft; a live shaft extending through and rotatable in said dead shaft andhaving one end adjacent and projecting from said free end of the dead shaft; a drive transmitting arm secured to the said projecting end of said drive shaft and extending radially outwardly to a point where its sweep path will be intercepted by said externally projecting drive tooth for engagement therewith; and an actuator member secured to the other end of said live shaft, for transmitting rotation through the live shaft to said tumbler; said tumblers having said peripheries each defined by a circumferential array of transverse V-notches in which said contact shoe is adapted to engage with a yielding detent-type holding and, tumbler-locating action.

7. A switch as defined in claim 6, wherein said contact shoe has a contact nose of rounded bar form, extending,

transversely, parallel to said V-notches and having a radius of curvature sufficiently small with respect to the gapof a V-notch so it will enter the notch to effect said holding action, said conductor segmentibeing of sheet metal formed with at least one V-notch conformed to the remaining V-notches of the tumbler periphery and positioned to conform to the uniform circumferential spacing and radial height of said remaining V-notches, said conductor segments being inset into said tumbler peripheries.

8. In a permutation switch: a case of cup shape having an end wall member at one end thereof and having a lateral wall member; a dead shaft of cylindrical sleeve form having one end fixed to said end wall member and having a free end adjacent the other end of the case;

a plurality of disc-like tumblers having respective cylindrical hub bores receiving said dead shaft and rotatable thereon, each of said tumblers having a generally cylindrical periphery provided with a shallow peripheral notch extending arcuately for a short portion of said periphery; a yoke of thin sheet material of dihedral-angular U-shape including a rectangular web portion seated in said notch and side ears extending radially inwardly from said Web in snug embracing engagement with said tumbler and secured to the respective sides thereof, said yoke and the remainder of said periphery constituting respective short and long segments, one of which is an insulator and the other a conductor; conductor brushes mounted in the case and each having at its end a contact shoe bearing upon a respective tumbler periphery for engagement alternatively with an insulator segment or a conductor segment depending upon the position of rotation of the respective tumbler; drive teeth carried by the respective tumblers, projecting axially therefrom in opposite directions, and interengageable for lost motion transmission of rotation between the respective tumblers for arranging the series of short segments in switch-actuating alignment, one of said drive teeth projecting externally from a terminal one of said tumblers disposed adjacent the said free end of said dead shaft; a live shaft extending through and rotatable in said dead shaft and having one end adjacent and projecting from said free end of the dead shaft; a drive transmitting arm secured to the said projecting end of said drive shaft and extend- 10 ing radially outwardly to a point where its sweep path will be intercepted by said externally projecting drive tooth for engagement therewith; and an actuator member secured to the other end of said live shaft, for transmitting rotation through the live shaft to said tumbler.

9. A permutation switch as defined in claim 8, wherein each tumbler has a pair of shallow flat radial recesses in its respective axial sides, communicating with said arcuate peripheral notches and wherein said yoke ears are received in said radial recesses with their outer faces flush with the side faces of the tumbler, and wherein each of said ears has an aperture and said tumbler has a pair of axially opposed, aligned integral projections extending from the bottoms of said radial recesses into said apertures and securing said short segments to the tumbler.

References Cited in the file of this patent UNITED STATES PATENTS 1,820,937 Cawley Sept. 1, 1931 2,452,747 Gomez Nov. 2, 1948 2,797,271 Augustine June 25, 1957 2,828,393 Wingard Mar. 25, 1958 2,844,671 Goral July 22, 1958 2,896,040 Jensen July '21, 1959 t FOREIGN PATENTS 692,074 Germany May 16, 1940 

